Component({
  options: {
    // 允许基础库识别 lifetimes 字段以支持 lifetimes 功能
    lifetimes: true
  },
  data: {
    canvasName: 'handWriting',
    ctx: '',
    canvasWidth: 0,
    canvasHeight: 0,
    transparent: 1, // 透明度 
    selectColor: 'black',
    lineColor: '#1A1A1A', // 颜色  
    lineSize: 1.5,  // 笔记倍数  
    lineMin: 0.5,   // 最小笔画半径 
    lineMax: 4,     // 最大笔画半径  
    pressure: 1,     // 默认压力  
    smoothness: 60,  //顺滑度，用60的距离来计算速度  
    currentPoint: {},
    currentLine: [],  // 当前线条
    firstTouch: true, // 第一次触发  
    radius: 1, //画圆的半径  
    cutArea: { top: 0, right: 0, bottom: 0, left: 0 }, //裁剪区域   
    bethelPoint: [],  //保存所有线条 生成的贝塞尔点；  
    lastPoint: 0,
    apFilePath: '', // 绘制成功导出的图片
    chirography: [], //笔迹 
    currentChirography: {}, //当前笔迹  
    linePrack: [] //划线轨迹 , 生成线条的实际点  
  },
  didMount() {
    const { screenWidth, screenHeight } = my.getSystemInfoSync()
    this.setData({
      screenWidth,
      screenHeight: screenHeight - 100
    })
  },
  lifetimes: {
    // 在组件在视图层布局完成后执行。
    ready() {
      let canvasName = this.data.canvasName
      let ctx = my.createCanvasContext(canvasName)
      this.setData({
        ctx
      })
      var query = my.createSelectorQuery();
      query.select('.handCenter').boundingClientRect().exec(rect => {
        console.log('handCenter-----', rect)
        this.setData({
          canvasWidth: rect[0].width,
          canvasHeight: rect[0].height
        }, () => {
          console.log('handCenter----', this.data.canvasWidth, this.data.canvasHeight)
        })
      })
    }
  },
  methods: {
    // 笔迹开始
    uploadScaleStart(e) {
      console.log('uploadScaleStart-----------', e)
      if (e.type != 'touchStart') return false;
      let ctx = this.data.ctx;
      ctx.setFillStyle(this.data.lineColor);  // 初始线条设置颜色 
      ctx.setGlobalAlpha(this.data.transparent);  // 设置半透明   
      let currentPoint = {
        x: e.touches[0].x,
        y: e.touches[0].y
      }
      let currentLine = this.data.currentLine;
      currentLine.unshift({
        time: new Date().getTime(),
        dis: 0,
        x: currentPoint.x,
        y: currentPoint.y
      })
      this.setData({
        currentPoint,
        // currentLine
      })
      if (this.data.firstTouch) {
        this.setData({
          cutArea: { top: currentPoint.y, right: currentPoint.x, bottom: currentPoint.y, left: currentPoint.x },
          firstTouch: false
        })
      }
      this.pointToLine(currentLine);
    },  // 笔迹移动
    uploadScaleMove(e) {
      if (e.type != 'touchMove') return false;
      if (e.cancelable) {
        // 判断默认行为是否已经被禁用      
        if (!e.defaultPrevented) {
          e.preventDefault();
        }
      }
      let point = {
        x: e.touches[0].x,
        y: e.touches[0].y
      }
      //测试裁剪    
      if (point.y < this.data.cutArea.top) {
        this.data.cutArea.top = point.y;
      }
      if (point.y < 0) this.data.cutArea.top = 0;
      if (point.x > this.data.cutArea.right) {
        this.data.cutArea.right = point.x;
      }
      if (this.data.canvasWidth - point.x <= 0) {
        this.data.cutArea.right = this.data.canvasWidth;
      }
      if (point.y > this.data.cutArea.bottom) {
        this.data.cutArea.bottom = point.y;
      }
      if (this.data.canvasHeight - point.y <= 0) {
        this.data.cutArea.bottom = this.data.canvasHeight;
      }
      if (point.x < this.data.cutArea.left) {
        this.data.cutArea.left = point.x;
      }
      if (point.x < 0) this.data.cutArea.left = 0;
      this.setData({
        lastPoint: this.data.currentPoint,
        currentPoint: point
      })
      let currentLine = this.data.currentLine
      currentLine.unshift({
        time: new Date().getTime(),
        dis: this.distance(this.data.currentPoint, this.data.lastPoint),
        x: point.x,
        y: point.y
      })
      this.setData({
        currentLine
      })
      this.pointToLine(currentLine);
    },
    // 笔迹结束
    uploadScaleEnd(e) {
      if (e.type != 'touchEnd') return 0;
      let point = {
        x: e.changedTouches[0].x,
        y: e.changedTouches[0].y
      }
      this.setData({
        lastPoint: this.data.currentPoint,
        currentPoint: point
      })
      let currentLine = this.data.currentLine
      currentLine.unshift({
        time: new Date().getTime(),
        dis: this.distance(this.data.currentPoint, this.data.lastPoint),
        x: point.x,
        y: point.y
      })
      this.setData({
        currentLine
      })
      //一笔结束，保存笔迹的坐标点，清空，当前笔迹    
      //增加判断是否在手写区域；    
      this.pointToLine(currentLine);
      var currentChirography = {
        lineSize: this.data.lineSize,
        lineColor: this.data.lineColor
      };
      var chirography = this.data.chirography
      chirography.unshift(currentChirography);
      this.setData({
        chirography
      })
      var linePrack = this.data.linePrack
      linePrack.unshift(this.data.currentLine);
      this.setData({
        linePrack,
        currentLine: []
      })
    },
    retDraw() {
      this.data.ctx.clearRect(0, 0, 700, 730)
      this.data.ctx.draw()
    },
    //画两点之间的线条；参数为:line，会绘制最近的开始的两个点；
    pointToLine(line) {
      this.calcBethelLine(line);
      return;
    },
    //计算插值的方式；
    calcBethelLine(line) {
      if (line.length <= 1) {
        line[0].r = this.data.radius;
        return;
      }
      let x0, x1, x2, y0, y1, y2, r0, r1, r2, len, lastRadius, dis = 0, time = 0, curveValue = 0.5;
      if (line.length <= 2) {
        x0 = line[1].x
        y0 = line[1].y
        x2 = line[1].x + (line[0].x - line[1].x) * curveValue;
        y2 = line[1].y + (line[0].y - line[1].y) * curveValue;
        //x2 = line[1].x;    
        //y2 = line[1].y;    
        x1 = x0 + (x2 - x0) * curveValue;
        y1 = y0 + (y2 - y0) * curveValue;
      } else {
        x0 = line[2].x + (line[1].x - line[2].x) * curveValue;
        y0 = line[2].y + (line[1].y - line[2].y) * curveValue;
        x1 = line[1].x;
        y1 = line[1].y;
        x2 = x1 + (line[0].x - x1) * curveValue;
        y2 = y1 + (line[0].y - y1) * curveValue;
      }
      //从计算公式看，三个点分别是(x0,y0),(x1,y1),(x2,y2) ；(x1,y1)这个是控制点，控制点不会落在曲线上；实际上，这个点还会手写获取的实际点，却落在曲线上
      len = this.distance({ x: x2, y: y2 }, { x: x0, y: y0 });
      lastRadius = this.data.radius;
      for (let n = 0; n < line.length - 1; n++) {
        dis += line[n].dis;
        time += line[n].time - line[n + 1].time;
        if (dis > this.data.smoothness) break;
      }
      this.setData({
        radius: Math.min(time / len * this.data.pressure + this.data.lineMin, this.data.lineMax) * this.data.lineSize
      });
      line[0].r = this.data.radius;
      //计算笔迹半径；  
      if (line.length <= 2) {
        r0 = (lastRadius + this.data.radius) / 2;
        r1 = r0;
        r2 = r1;
        //return;    
      } else {
        r0 = (line[2].r + line[1].r) / 2;
        r1 = line[1].r;
        r2 = (line[1].r + line[0].r) / 2;
      }
      let n = 5;
      let point = [];
      for (let i = 0; i < n; i++) {
        let t = i / (n - 1);
        let x = (1 - t) * (1 - t) * x0 + 2 * t * (1 - t) * x1 + t * t * x2;
        let y = (1 - t) * (1 - t) * y0 + 2 * t * (1 - t) * y1 + t * t * y2;
        let r = lastRadius + (this.data.radius - lastRadius) / n * i;
        point.push({ x: x, y: y, r: r });
        if (point.length == 3) {
          let a = this.ctaCalc(point[0].x, point[0].y, point[0].r, point[1].x, point[1].y, point[1].r, point[2].x, point[2].y, point[2].r);
          a[0].color = this.data.lineColor;
          this.bethelDraw(a, 1);
          point = [{ x: x, y: y, r: r }];
        }
      }
      this.setData({
        currentLine: line
      })
    },
    //求两点之间距离
    distance(a, b) {
      let x = b.x - a.x;
      let y = b.y - a.y;
      return Math.sqrt(x * x + y * y);
    },
    ctaCalc(x0, y0, r0, x1, y1, r1, x2, y2, r2) {
      let a = [], vx01, vy01, norm, n_x0, n_y0, vx21, vy21, n_x2, n_y2;
      vx01 = x1 - x0; vy01 = y1 - y0;
      norm = Math.sqrt(vx01 * vx01 + vy01 * vy01 + 0.0001) * 2;
      vx01 = vx01 / norm * r0;
      vy01 = vy01 / norm * r0;
      n_x0 = vy01;
      n_y0 = -vx01;
      vx21 = x1 - x2;
      vy21 = y1 - y2;
      norm = Math.sqrt(vx21 * vx21 + vy21 * vy21 + 0.0001) * 2;
      vx21 = vx21 / norm * r2;
      vy21 = vy21 / norm * r2;
      n_x2 = -vy21;
      n_y2 = vx21;
      a.push({ mx: x0 + n_x0, my: y0 + n_y0, color: "#1A1A1A" });
      a.push({ c1x: x1 + n_x0, c1y: y1 + n_y0, c2x: x1 + n_x2, c2y: y1 + n_y2, ex: x2 + n_x2, ey: y2 + n_y2 });
      a.push({ c1x: x2 + n_x2 - vx21, c1y: y2 + n_y2 - vy21, c2x: x2 - n_x2 - vx21, c2y: y2 - n_y2 - vy21, ex: x2 - n_x2, ey: y2 - n_y2 });
      a.push({ c1x: x1 - n_x2, c1y: y1 - n_y2, c2x: x1 - n_x0, c2y: y1 - n_y0, ex: x0 - n_x0, ey: y0 - n_y0 });
      a.push({ c1x: x0 - n_x0 - vx01, c1y: y0 - n_y0 - vy01, c2x: x0 + n_x0 - vx01, c2y: y0 + n_y0 - vy01, ex: x0 + n_x0, ey: y0 + n_y0 });
      a[0].mx = a[0].mx.toFixed(1);
      a[0].mx = parseFloat(a[0].mx);
      a[0].my = a[0].my.toFixed(1);
      a[0].my = parseFloat(a[0].my);
      for (let i = 1; i < a.length; i++) {
        a[i].c1x = a[i].c1x.toFixed(1);
        a[i].c1x = parseFloat(a[i].c1x);
        a[i].c1y = a[i].c1y.toFixed(1);
        a[i].c1y = parseFloat(a[i].c1y);
        a[i].c2x = a[i].c2x.toFixed(1);
        a[i].c2x = parseFloat(a[i].c2x);
        a[i].c2y = a[i].c2y.toFixed(1);
        a[i].c2y = parseFloat(a[i].c2y);
        a[i].ex = a[i].ex.toFixed(1);
        a[i].ex = parseFloat(a[i].ex);
        a[i].ey = a[i].ey.toFixed(1);
        a[i].ey = parseFloat(a[i].ey);
      }
      return a;
    },
    bethelDraw(point, is_fill, color) {
      let ctx = this.data.ctx;
      ctx.beginPath();
      ctx.moveTo(point[0].mx, point[0].my);
      if (undefined != color) {
        ctx.setFillStyle(color);
        ctx.setStrokeStyle(color);
      } else {
        ctx.setFillStyle(point[0].color);
        ctx.setStrokeStyle(point[0].color);
      }
      for (let i = 1; i < point.length; i++) {
        ctx.bezierCurveTo(point[i].c1x, point[i].c1y, point[i].c2x, point[i].c2y, point[i].ex, point[i].ey);
      }
      ctx.stroke();
      ctx.restore();
      if (undefined != is_fill) {
        ctx.fill();   //填充图形 ( 后绘制的图形会覆盖前面的图形, 绘制时注意先后顺序 )    
      }
      ctx.draw(true)
    },
    // 保存按钮
    subSure() {
      this.data.ctx.toTempFilePath({
        destWidth: 375,
        destHeight: 812,
        success: (res) => {
          console.log(res)
          my.previewImage({
            current: 0,
            urls: [res.apFilePath],
            complete: resp => {
              console.log(resp)
            }
          })
        }
      })
    },
    selectColorEvent(event) {
      console.log(event)
      var color = event.currentTarget.dataset.colorValue;
      var colorSelected = event.currentTarget.dataset.color;
      this.setData({
        selectColor: colorSelected,
        lineColor: color
      })
    }
  },
  events: {
    onBack() {
      console.log('触发了onBack')
    }
  }
})